Hardware items should not have owners.

Whenever someone adds a piece of hardware, a page should be created but, after that, everybody who wants to add information or share their experience with that hardware should be able to do it in the same page.

That way, for example, if a user reports a problem with a certain piece of hardware and there's a how-to or a forum debate about that elsewhere they could be linked, or summarised in the very same page.

I totally agree and another proposed idea was to upload hardware info. I would say that combining the two would provide the best results. If someone notes an issue in a hardware that I have, my account could get a message noting a potential issue in my system. That way resolving issues would be quicker for all individuals.

I agree that uploaded hardware performance information should not be attributed to specific owners. (except in their My_____ pages, where they should retain the ability to update and edit their uploaded information)
Essentially this seems like just another permutation of the idea that we need an integrated database potential new users, and others, can use to discover which hardware can be expected to work best with Mint right "out of the box".
It sounds like a good idea, that would be difficult to implement.
Using the voting approach suggested by Xyie might help keep it manageable, listing only the tallied statistics, followed by the hardware user's reviews.

Yes,comments should be allowed on each page and basically,there should be only one page for every hardware for all Mint distributions to make hardware list shorter.Otherwise it will become,with time,bloated.

Maybe something like a voting on hardware performance (showing the statistics) based on each person's review, where the reviews show up on a single page. This would obviously require confirmation and/or a search method to verify whether the hardware is the same. This way, a hardware's performance can be tracked easier at a glance on a single page, rather than tracking down any number of pages related to said hardware. A comments section on the same page would be beneficial as well. However, after a certain length, the page becomes too long with hardware reviews. Thus, if this were to be added, multiple pages for the same thing must be available as necessary for additional hardware reviews.

I think the best and easiest way to implement this would be to have a Comments section on the page, like Ideas do. This would enable others to leave their experiences and the OP to possibly update their post if they feel they have something relevant.

Good idea. Centralizing all information about hardware would be user-friendlier. In practice, it's quite easy to shift focus from the personal hardware list to the global one. All the data would need to be stored in a table and a new table could store the user experience with the hardware. This is rather a data migration to a new DB structure.